The present invention relates to a trim used for protecting, trimming and sealing edge portions, joint portions and the like of automobiles, furniture and the like or used for attaching weather stripping or other similar articles to various types of straight or curved structures.
In the trim of the above described type, a core member is embedded in a main body of rubber or synthetic resin in order to provide good shape-retentivity thereof.
The trim is required to be flexible and deformable in accordance with the contour of the place where the trim is to be attached.
Therefore, the core member embedded in the trim must not obstruct the trim from readily and freely bending or twisting.
In order to satisfy the above described demands, various types of core members have been used or proposed.
Conventional core members D and E as shown in FIG. 1 and FIG. 2 are obtained by punching a metallic plate by means of a punch.
The conventional core member D comprises a large number of strip-shaped members 1 which are integrally connected by bridge portions 2a in the central portions thereof in a width direction of the core member D.
In the conventional core member E, a large number of strip-shaped members 1 are integrally connected by bridge portions in both end portions thereof.
And by covering such a core member as described above with a covering material such as rubber or synthetic resin, and bending it so as to have a desired cross-sectional shape such as a u-shape, a channel-shaped trim can be obtained.
These core members can be produced easily. And they are so strong that they do not deform when they are covered with the covering material.
Futhermore, trims wherein these core members are embedded have good shape-retentivity.
However, these conventional trims cannot be freely expanded nor contracted in a longitudinal direction thereof. And also, they do not bend flexibly.
Another conventional core members F and G as shown in FIG. 3 and FIG. 4 overcome the above described defect of the conventional core members D and F.
In the conventional core member F as shown in FIG. 3, a large number of transversely extending slots 31 having the same length in a transverse direction of the trim are perforated in the metallic plate at predetermined intervals to form bridge portions 2c in both side end portions of the thin plate.
And in the spaces between both ends of the slots 31 and both side edges of the plate, a large number of concave portions 4 are provided to form thin walled portions which are easily broken by an outer force.
And after the core member F is covered with a covering material, an outer force is applied to the covered core member so as to break it in the concave portions 4. As a result, the trim wherein strip-shaped core pieces are disconnectedly embedded can be obtained.
The conventional core member G as shown in FIG. 4, is formed by perforating a large number of transversely extending slots 32 having the same length in a transverse direction of the core member G, in a band-shaped metallic plate at predetermined intervals and providing narrow bridge portions 2d in both sides of the slots 32 in a transverse direction of the metallic plate.
And after the core member G is covered with a covering material, the covered bridge portions 2d are removed from the covered core member from alternate long and two short dashes lines drawn on FIG. 4 by means of cutting or scraping means.
As a result, a trim wherein a large number of strip-shaped core pieces are embedded disconnectedly can be obtained.
The trim comprising the above described core members F and G can freely expand, contract and bend. However, it is difficult to determine the depth of the concave portions 4 to be perforated in the core member F. If the concave portions 4 are perforated too deep, the core member F is easily broken or deformed in the process of supplying it to the covering process or in the following process of covering the core member. As a result, production efficiency is largely lowered.
And if the concave portions 4 are perforated too shallow, the core member F cannot be broken with ease when the outer force is applied to the covered core member.
And in order to obtain a trim comprising the core member G, the process of removing the bridge portions 2d is required additionally.
Since the bridge portions 2d are removed after the core member G is covered, considerably large volume of the material for the core member and covering material is wasted so that the cost of the obtained trim becomes increased.
Furthermore, in the trim comprising the core member G, the core member is exposed from both side edges of the trim so that the core member is apt to rust. And also when the trim is attached to some structures, they are in danger of being damaged by the exposed core member.
And in each of the core members F and G, the strip-shaped core pieces which are embedded in a covering material disconnectedly are apt to slip relative to each other therewithin.
For example, when the trim including the core members F or G is attached to a curved place having a large curvature, the covering material of the curved inner surface of the trim becomes wrinkled since the core pieces are piled up with each other therein.
Accordingly, an object of the present invention is to provide an improved method for producing a trim which flexibly deforms, freely expands and contracts in accordance with the contour of the place to which it is to be attached, with desirable shape-retentivity.
Another object of the present invention is to provide an improved method for producing a trim wherein disconnectedly arranged core pieces are embedded without slipping relative to each other with good production efficiency.